【作者】 于文博；

【导师】 赵旦峰；

【作者基本信息】 哈尔滨工程大学 ， 通信与信息系统， 2005， 硕士

【摘要】 正交频分多路复用是一种多载波调制技术,由于具有很高的频谱利用率,很强的抗多径延迟能力,已经广泛的应用在数字音频广播、数字电视以及无线局域网当中。 然而,OFDM一个缺点就是对于同步错误非常敏感,特别是对于频率偏差。当存在同步错误时,子载波之间的正交性遭到破坏,从而引起严重的载波间干扰,使解调性能大大下降。因而性能良好的同步方法对于OFDM系统是非常重要的。 论文首先阐述了正交多载波调制OFDM技术适用于高速数据传输的原理,着重讨论了OFDM中的同步问题,对常规的同步方案作了讨论,并对这些算法进行了分析比较,通过仿真验证了算法的性能。在此基础之上提出了一个基于循环平稳的OFDM定时偏移和频率偏移的联合估计算法,并进行了计算机仿真。最后对OFDM在IEEE802.11a中的应用作了介绍。更多还原

【Abstract】 Orthogonal frequency division multiplexing (OFDM) is a multi-carrier modulation method. Due to variety of it’sadvantages such as high bandwidth efficiency and robustness against multi-path delay, it has been widely used in the fields of digital audio broadcasting, digital television and wireless local area networks and is likely to become one of key technologies of Fourth Generation mobile communications.However, one of the drawbacks of OFDM is the sensitivity to synchronization error, especially tofrequency offset. When a synchronization error exists, the orthogonality between sub-carriers can’t be maintained, serious inter-carrier interference is introduced and demodulation performance will be degraded greatly. So perfect synchronization methods are essential to OFDM system.Firstly, this paper presents the principle of multi-carrier modulation technique-OFDM-applying to high bit rate transmission. The emphases are focused on the synchronization in OFDM technique. And this thesis studies, analyses and compares some synchronization methods. Many simulations are taken, the performances are given by simulation results, and some conclusions are given. Then Base on the cyclostationarity of OFDM symbol, a synchronization algorithm for the joint estimation of timing offset and frequency offset is proposed and discussed in detail and given the simulation results. Finally, the application of OFDM to IEEE802.11a Wireless Local Area Network is introduced.更多还原